Uji pengeringan benih Kopi Arabika dengan praperlakuan ABA dan pasca perlakuan Osmoconditioning

KURNIAWAN, Trisda, Dr.Ir. Aziz Purwantoro, MSc

2004 | Tesis | S2 Agronomi

Suatu penelitian dengan tujuan mempelajari peran ABA dan osmoconditioning dalam tiga aras penurunan kadar air, serta interaksi antara ketiganya terhadap viabilitas benih kopi arabika, telah dilaksanakan di lingkungan Fakultas Pertanian, Universitas Gadjah Mada, dari bulan Mei sampai Juli 2004. Penelitian ini menggunakan rancangan acak lengkap pola faktorial dengan tiga faktor, yaitu: 2 aras konsentrasi ABA (H): 0 ppm (H0) dan 10 ppm (H10), 3 aras pengeringan (kadar air) benih (P): 14% (P14), 12% (P12) dan 10% (P10) dan 4 aras durasi osmoconditioning (O): kontrol (O0), 3 hari (O3), 5 hari (O5) dan 7 hari (O7), dengan 3 ulangan. Pengamatan dilakukan terhadap kadar prolin, pati, protein, asam lemak bebas, α-tokoferol, asam askorbat, kecepatan respirasi, daya hantar listrik dan daya tumbuh benih. Data yang diperoleh dianalisis melalui analisis ragam dan terhadap pengaruh yang telah nyata pada aras 5% dilanjutkan dengan uji jarak Duncan (DMRT) pada aras 5%. Hasil penelitian menunjukkan bahwa pengeringan benih kopi arabika sampai kadar air di bawah 14% menyebabkan penurunan viabilitasnya. Tidak saja menyebabkan tingginya akumulasi asam-asam lemak bebas dan meningkatkan kebocoran membran, tetapi juga menurunkan kadar α-tokoferol, pati, dan daya tumbuh benih. Sungguhpun demikian ABA berperan penting dalam meningkatkan toleransi benih kopi arabika terhadap pengeringan di bawah 14% dengan meningkatkan kadar prolin, menurunkan kecepatan respirasi, mempertahankan kandungan pati, dan meningkatkan kadar α-tokoferol benih, sehingga mencegah akumulasi asam-asam lemak bebas dan meminimalkan kebocoran membran, yang pada akhirnya mampu mempertahankan daya tumbuh benih tetap tinggi. Osmoconditioning tidak menunjukkan peran penting dalam perbaikan viabilitas benih apabila sebelum pengeringan telah diaplikasika ABA. Tanpa aplikasi ABA sebelum pengeringan, osmoconditioning berperan penting dengan meningkatkan kandungan α-tokoferol dan “memperbaiki” kebocoran membran sehingga daya tumbuh benih menjadi lebih baik. Ditinjau dari segi daya tumbuh benih, osmoconditioning dapat menggantikan fungsi ABA bila kadar air benih hanya diturunkan sampai 12%.

A research aimed to study the role of ABA and osmoconditioning in three moisture content levels, and interaction between them on Arabica coffee seed viability, had been done at the Agriculture Faculty of Gadjah Mada University, from May to July 2004. This research conducted by using factorial completely randomized design with three treatments i. e: 2 levels of ABA concentration (H): 0 ppm (H0) and 10 ppm (H10), 3 levels of desiccation (water content) (P): 14% (P14), 12% (P12) and 10% (P10), and 4 levels of osmoconditioning duration (O): control (O0), 3 day (O3), 5 day (O5) and 7 day (O7), with 3 replicates. Parameters used in this research were proline content, starch, protein, free fatty acid, α-tocopherol, ascorbic acid, respiration rate, electrical conductivity and emergence ability. Data was analyzed by analysis of variance and to every effect which was significant at the level of 5%, continued with Duncan Multiple Range Test at the level of 5%. The results showed that Arabica coffee seed desiccation to water content below 14% had damaging effect to viability. Not only caused the high accumulation of free fatty acids and increased membrane leakage, but also decreased the seed content of α-tocopherol, starch, and emergence ability. Eventhough, ABA had important roles in increasing Arabica coffee seed tolerance to desiccation below 14% by increasing proline content, decreasing respiration rate, maintaining starch content, and increasing α-tocopherols content of seed, that prevent the accumulation of free fatty acids and minimized membrane leakage, that in the end maintained seed emergence ability stayed high. Osmoconditioning did not showed important role in seed viability repairmen if ABA had been applicated before desiccation. Without ABA application before desiccation, osmoconditioning had important role by increasing α-tocopherols content and “fixing” membrane leakage that made seed emergence ability better. At the side of seed emergence ability, osmoconditioning could substitute the role of ABA if seed water content only decreased to 12%.

Kata Kunci : Benih Kopi Arabika,Pengeringan,ABA, desiccation, ABA, osmoconditioning, non ortodok, Coffea arabica